Abstract: A telephone is disclosed having an automatic gain control circuit and a processor which separates a local signal into a sound signal and a speech signal. The automatic gain control circuit selects a gain value based on sound levels of the sound signal when the speech signal indicates an absence of speech. The telephone also has a variable gain amplifier to amplify a received signal. The gain of the amplifier is selected from stored gain values which are stored in a memory of the telephone in a table format and are a function of the sound signal and volume levels of the sound signal chosen by a user. An input device of the telephone allows the user to select one of the volume levels.

Abstract: A method of controlling automatic state returns relates to a dynamic system coupled to an automatic control operating in a discrete negative feedback mode. The method includes a phase for defining a controller, and a phase for operating the system. The defining phase is realized in an open-loop learning phase which includes a step of reading states in which a system may be situated, and a step of generating commands for returning the system to an ideal state. When the commands generating step takes place, the method supplies, for each state, a sequence of discrete commands which are determined by imposing a constraint intended to reduce the error relative to that state below a predetermined threshold.